Tamang, a close aide of GJM chief Bimal Gurung, had launched the fast on October 30 at the correctional home alleging that the case against him was farce and demanding his immediate release.
He was admitted to the Jalpaiguri sadar hospital the next day as his blood pressure had gone down. He is still in hospital and is under observation, Sarkar said.
Tamang was arrested on August 22 for alleged involvement in the burning of the forest bungalow at Takdah.
He was elected the chief executive of Gorkha Territorial Administration (GTA) on September 27 after Gurung quit but could not take oath within the stipulated one-month time as he was in lodged in Jalpaiguri correctional home.